Sort of rack mounted...
I have the X2 Wireless, the original unit they made before Line 6 bought them out. I have the AC Powered version, the XDS Plus, I believe it is called. It works very well, and is an interesting alternative as you can either put the steel cased receiver on your pedal board (it is about the size of a TC 2290 Chorus), or velcro it (as I do) in a 1 space rack shelf and put it in your rack. The unit is no longer made, and the Line 6 isn't exactly the same, but it is available here and there at a decent price.
They did also make a rack version, but it is much more rare to see them. There was also a cheaper one (XDS95) but it was all plastic and just didn't seem like it would hold up, not to mention it was battery powered on both ends.
I like it so much I bought a second unit to use if this one ever craps out!